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<head>
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    <title>Document</title>
    <style>
        #box {
            width: 200px;
            height: 200px;
            background-color: red;
        }
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        console.log(window.devicePixelRatio); //像素比
        // 像素比 原先1px的内容，放大到devicePixelRatio px显示
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</head>

<body>
    <div id="box"></div>
</body>

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